solar powered greenhouse fan
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- čas přidán 15. 06. 2020
- I use a 100W 12v solar panel to drive an automotive 12v DC fan to pull how air out of my greenhouse. The wiring/control system is simple - a single switch to interrupt current. Ventilation isn't needed on cloudy days, and the panel doesn't generate enough current to spin the fan hard on those days. The system is turned on from about April to September and has been in operation for at least a year and a half with no problems.
In the winter I block the fan opening with a piece of rigid pink foam insulation.
Greenhouse is about 12x18 with an 1:6 pitch, 8' at peak, 6' at the sunny side wall. Greenhouse faces south-southwest. The design isn't optimal for the 44th parallel - too much sun in the summer and not enough (roof) insulation in the winter. A better design would have been to do the upper half of the greenhouse roof with metal roofing (over 1" rigid insulation?) and only have polycarbonate on the lower half of the roof.
This is equivalent to the solar panel I bought: www.amazon.com/Newpowa-Polycr...
This is equivalent to the DC fan I used: www.amazon.com/Electric-Radia...
Solar wire is easy to work with, but expensive! www.amazon.com/iGreely-MC4-Ex...
And of course the stupid mounting brackets to mount the panel to the roof, www.amazon.com/Renogy-RNG-MTS...
This project was initially inspired by this magazine article, www.autoweek.com/car-life/but... and the absurdly high cost of pre-packaged vents at the ag and greenhouse supply companies.
Straight to the point I like it 👍👍
Exactly what I was looking for. Thanks!
So how did you splice the panel into the fan wiring...just red on red and black on black.
Yep, but I interrupted the power with an "all-weather" electric outlet switch. The fan wiring leaves a lot to be desired in terms of labelling - probably a good idea to do a dry run in the backyard before putting the panel up on the roof. As I recall, the fan I bought works with both polarities, but you get way more air movement in one setup.
I might have tied the black solar panel wire to the building's ground rod - can't remember.
Any idea how much it cooled your greenhouse?
I haven't measured. Without the fan it easily gets above 100F on a 70F sunny afternoon.
is the radiator fan directly connected to solar panel? isn't it broken due to flactuating voltage?
No, it works just fine under fluctuating voltage. I did wire in a cutoff switch on the positive line, but there's nothing else in the circuit.
What kind of connections did you use to connect the fan wires to the heavier gauge wire that you run to the switch?
Standard outdoor wiring box and wire nuts
What size panel is feeding that?
100W
What's the approx size of your green house?
12ft deep, 18ft wide, slope is 8ft down to 6ft. I didn't think very hard about these dimensions while building it - I probably have too much solar gain from May to August, and the 1:6 pitched roof doesn't really get me extra sun in November-March. I could have done the roof half steel with little loss in function.
Awesome idea but the Link to the fan doesn’t work.
Any 12v automotive radiator fan will work.
How is this working after 2yrs?
Just fine, no problems. Think about a radiator fan on a 10 year old car - only needs to be replaced if you hit a deer.
Your solar panel details, please
Generic 100W panels from Amazon.